Method, Controller, and System for Tunnel Communication

ABSTRACT

A communication system for allowing personnel in a tunnel below ground to communicate with a location above ground includes a controller disposed below ground in the tunnel. The system includes an uplink portion that sends uplink messages from the controller below ground in the tunnel through earth to above ground. The system includes a downlink portion through which downlink messages are sent from above ground through earth to the controller below ground in the tunnel. The system includes a personnel communication portion through which downlink messages are sent from the controller wirelessly to the personnel as personnel messages and personnel messages are received wirelessly by the controller from the personnel below ground in the tunnel. A controller for allowing personnel in a tunnel below ground to communicate with a location above ground. A method for allowing personnel in a tunnel below ground to communicate with a location above ground.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application of U.S. patent application Ser. No.13/743,947 filed Jan. 17, 2013, now U.S. Pat. No. 9,118,409,incorporated by reference herein.

FIELD OF THE INVENTION

The present invention is related to a communication system for allowingpersonnel in a mine, tunnel or other space below ground to communicatewith a location above ground. (As used herein, references to the“present invention” or “invention” relate to exemplary embodiments andnot necessarily to every embodiment encompassed by the appended claims.)More specifically, the present invention is related to a communicationsystem for allowing personnel below ground to communicate with alocation above ground that includes a controller which controls messageflow between the personnel below ground and above ground.

BACKGROUND OF THE INVENTION

This section is intended to introduce the reader to various aspects ofthe art that may be related to various aspects of the present invention.The following discussion is intended to provide information tofacilitate a better understanding of the present invention. Accordingly,it should be understood that statements in the following discussion areto be read in this light, and not as admissions of prior art.

In mines, it is imperative that communication exists between the minersthat are in the mine below ground and to people above ground.Specifically, in emergency situations, it is critical to be able tocommunicate with the miners to know whether they have been injured,where they are located, whether they are trapped, and whether they needfood, water, air or first aid, to name but a few of the possible needsof the miners in such situations.

The problem that exists with communication in a mine is that the earthitself can impede communication between the miners in the mine as wellas between the miners in the mine and people above the ground. Cablingor wiring has traditionally been used, but it requires a connectionbetween the communication points. If the communication points areseparated by a significant distance, it becomes problematic to extendthe wiring such distances. Moreover, since mines are constantlyexpanding and changing shape, wiring is constantly being run toaccommodate the changing distances and configurations of the mine. Inaddition, mines are hazardous places, with rockfall possibly damaging orcutting wires, which could be very dangerous in emergency situationswhere the communication is badly needed. Furthermore, it is impracticalto extend wires to each miner in a mine to be able to communicate witheach miner at any time. Although the specific need that gave rise to theinvention was first identified in the mining industry, the utility ofthe invention could apply equally to emergency situations involvingpersonnel in an underground work location, such as tunnels.

Wireless communication would eliminate the problems associated withusing cabling or wiring for communication in a mine, but the very earthitself imposes difficulties on wireless communication between miners inthe mine, and miners in the mine and people above ground.

BRIEF SUMMARY OF THE INVENTION

The present invention pertains to a communication system for allowingpersonnel in a tunnel below ground to communicate with a location aboveground. The system comprises a controller disposed below ground in themine. The system comprises an uplink portion that sends uplink messagesfrom the controller below ground in the tunnel through the earth toabove ground. The controller is in communication with the uplinkportion. The system comprises a downlink portion through which downlinkmessages are sent from above ground through earth to the controllerbelow ground in the tunnel. The controller is in communication with thedownlink portion. The system comprises a personnel communication portionthrough which downlink messages are sent from the controller wirelesslyto the personnel as personnel messages and personnel messages arereceived wirelessly by the controller from the personnel below ground inthe tunnel. The controller is in communication with the personnelcommunication portion.

The present invention pertains to a method for allowing personnel in atunnel below ground to communicate with a location above ground. Themethod comprises the steps of sending uplink messages from a controllerthrough an uplink portion below ground in the tunnel through earth toabove ground. The controller in communication with the uplink portion.There is the step of sending messages from above ground through earth tothe controller through a downlink portion below ground in the tunnel,the controller in communication with the downlink portion. There is thestep of sending from the controller through a personnel communicationportion wirelessly to the personnel downlink messages as personnelmessages. The controller in communication with the personnelcommunication portion. There is the step of receiving wirelessly by thecontroller from the personnel below ground in the tunnel personnelmessages.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

In the accompanying drawings, the preferred embodiment of the inventionand preferred methods of practicing the invention are illustrated inwhich:

FIG. 1 is a block diagram of the system of the present invention.

FIG. 2 is a schematic representation of the system of the presentinvention.

FIG. 3 is a block diagram of the system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings wherein like reference numerals refer tosimilar or identical parts throughout the several views, and morespecifically to FIGS. 1 and 2 and 3 thereof, there is shown acommunication system 10 for allowing personnel, such as miners, in atunnel, for instance in a mine, below ground to communicate with alocation above ground. The system 10 comprises a controller 12 disposedbelow ground in the tunnel. The system 10 comprises an uplink portion 14that sends uplink messages from the controller 12 below ground in thetunnel through earth to above ground. The controller 12 in communicationwith the uplink portion 14. The system 10 comprises a downlink portion16 through which downlink messages are sent from above ground throughearth to the controller 12 below ground in the tunnel. The controller 12in communication with the downlink portion 16 of the system 10 comprisesa personnel communication portion 18 through which downlink messages aresent from the controller 12 wirelessly to the personnel as personnelmessages and personnel messages are received wirelessly by thecontroller 12 from the personnel below ground in the tunnel, thecontroller 12 in communication with the personnel communication portion18.

The controller 12 may be disposed in an intrinsically safe enclosure,such as an explosion proof enclosure 20. The controller 12 may include aprocessing unit 22 which takes downlink messages received from thedownlink portion 16 and transmits the downlink messages as personnelmessages to the personnel, and which takes personnel messages receivedfrom the personnel communication portion 18 and transmits the personnelmessages as uplink messages above ground through the uplink portion 14.The controller 12 may include an uplink interface 24 through whichuplink messages are provided to the uplink portion 14, a downlinkinterface 26 through which downlink messages are received from thedownlink portion 16, and a personnel communication interface throughwhich personnel messages are sent to and received from the personnelcommunication portion 18.

The processing unit 22 may broadcast out the downlink messages aspersonnel messages to all personnel through the personnel communicationportion 18. The personnel communication portion 18 may include apersonnel communicator 28 disposed with each personnel that sends aresponse to each personnel message received from the controller 12 backto the controller 12 through the personnel communication portion 18. Theresponse may be either positive or negative, for instance red or green,respectively, and the processing unit 22 counts the responses that aregreen which were received over a predetermined time period and sends anuplink message at a frequency which corresponds to a number of responsescounted in the predetermined time that are green which were received bythe controller 12.

The downlink portion 16 may use magnetic induction to send the aboveground message to the tunnel. The uplink portion 14 may use seismicwaves to send the below ground message to above ground. The system 10may include a battery and the controller 12 includes a relay bank whichprevents electrical feedback from the battery to the controller 12.

The present invention pertains to a controller 12 for allowing personnelin a tunnel below ground to communicate with a location above ground.The controller 12 comprises an uplink interface 24 through which uplinkmessages are sent to the location above ground. The controller 12comprises a downlink interface 26 through which downlink messages arereceived from above ground. The controller 12 comprises a personnelcommunication interface through which personnel messages are sent to andreceived from the personnel below ground in the tunnel. The controller12 comprises a processing unit 22 which takes downlink messages receivedfrom the downlink interface 26 and transmits the downlink messages aspersonnel messages to the personnel through the personnel communicationinterface, and which takes personnel messages received from thepersonnel communication interface and transmits the personnel messagesas uplink messages above ground through the uplink interface 24.

The present invention pertains to a method for allowing personnel in atunnel below ground to communicate with a location above ground. Themethod comprises the steps of sending uplink messages from a controller12 through an uplink portion 14 below ground in the tunnel through earthto above ground. The controller 12 is in communication with the uplinkportion 14. There is the step of sending messages from above groundthrough earth to the controller 12 through a downlink portion 16 belowground in the tunnel, the controller 12 in communication with thedownlink portion 16. There is the step of sending from the controller 12through a personnel communication portion 18 wirelessly to the personneldownlink messages as personnel messages. The controller 12 is incommunication with the personnel communication portion 18. There is thestep of receiving wirelessly by the controller 12 from the personnelbelow ground in the tunnel personnel messages.

There may be the steps of a processing unit 22 of the controller 12taking downlink messages received from the downlink portion 16 andtransmitting the downlink messages as personnel messages to the miners,and taking personnel messages received from the personnel communicationportion 18 and transmitting the personnel messages as uplink messagesabove ground through the uplink portion 14. There may be the steps ofthe controller 12 providing uplink messages to the uplink portion 14through an uplink interface 24 of the controller 12, providing downlinkmessages received from the downlink portion 16 to the processing unit 22through a downlink interface 26 of the controller 12, sending personnelmessages to the personnel from the processing unit 22 through apersonnel communication interface of the controller 12; and receivingpersonnel messages from the personnel by the processing unit 22 throughthe personnel communication portion 18.

There may be the step of the processing unit 22 broadcasting out thedownlink messages as personnel messages to all personnel through thepersonnel communication portion 18. The personnel communication portion18 may include a personnel communicator 28 disposed with each personneland including the step of sending from the personnel communicators 28 aresponse to each personnel message received from the controller 12 backto the controller 12 through the personnel communication portion 18. Theresponse may be either red or green, and there may be the steps of theprocessing unit 22 counting the responses that are green which werereceived over a predetermined time period and sending an uplink messageat a frequency which corresponds to a number of responses counted in thepredetermined time that are green which were receives by the controller12. There may be the step of preventing electrical feedback from abattery to external power with a relay bank of the controller 12.

Referring to FIG. 1, the controller 12 consists of three maincommunication interfaces. The first, the downlink interface 26, is anRS-232 serial connection to the RX downlink equipment/antenna 30. When amessage is sent from the surface, it is received through the RX downlinkequipment/antenna 30 and transmitted to a processing unit 22 of thecontroller 12 through this RS-232 connection. The message typetransmitted is a text message. This message is then sent to the PODCommunicator 32 (CommTrac Interface) also through an RS-232 connection.From here the message is broadcast out to all of the miners on theirMiner Communicator 28. Each miner will generate a response to this textmessage(green or red) that will be received through the POD Communicator32 and sent back to the through the RS-232 connection. The processingunit 22 will then accumulate the number of green responses over a 2minute period. It will then turn-on and control the frequency generator34 which generates a frequency that will be received on the surface(uplink). The processing unit 22 will set the digital outputs thatcorrespond to one of the twenty desired frequencies. Each frequencycorresponds to the number of green responses. For example, 0-3 greenresponses are 1 frequency and 4-6 green responses are a secondfrequency.

The green and red response is utilized for a yes/no to answer a questionsent to a miner. For example, the message “Are you hurt?” might be sentto the miner from the surface. When received by the miner he will eitherpress green for yes or red for no. These responses are sent back to theprocessing unit 12 using CommTrac. The data is then accumulated usingthe microcontroller and the number of yes responses is sent to thesurface using a corresponding frequency. The specific frequency/tone issent using the uplink seismic transducer 36 (the subwoofer).

Uplink Data is sent as a frequency or tone. This tone corresponds tosome known canned data. Downlink data is sent as ASCII text. Thisdownlink data is then converted to a CommTrac text message. Downlinktext messages are converted to Miner Terminated Text Messages to be sentover the personnel communication portion 18, which is preferably aCommTrac network. Miners will then respond with the Miner TerminatedText/Configuration Acknowledgement Message. These responses are thegreen/red responses that are accumulated in the non-transient memory 36of the controller 12 and mapped to a frequency to be sent to the surfaceabove ground. Commtrac, which provides communication between the minersin the tunnel and the controller 12, is well known in the art and may bepurchased from Strata Products Worldwide, LLC in Sandy Springs, Ga.

Other functions the controller 12 provides are battery monitoring 40 andpower sense 42. It is connected to the battery 44 and a message is sentthrough the CommTrac network every 30 minutes to the controller 12providing battery health information. It also is constantly monitoring aswitch 46 to determine if power is present. This allows the controller12 to know when to operate.

In regard to FIG. 1, the 120 VAC mine power 48 is a source ofelectricity for the system 10 from the mine. Electricity is fed to asurge protector 50 and then to a triple redundant relay bank 52 of thecontroller 12. The triple redundant relay bank 52 prevents electricalfeedback from the batteries 44 to the equipment in the event thatelectricity from the mine is turned off or terminated, for example in adisaster event, so electrical feedback to the equipment will not cause adangerous condition and potentially trigger an explosion in the mine.

The part numbers for the EMS system, battery, and surge protector are,respectively:

-   -   Elite Power Systems EMS-4-V2    -   Elite Power Systems GBS-LFMP100AH    -   Sola-HD STFE050-10N

Electricity from the triple redundant relay bank 52 is then fed to abattery charger 54, and from the battery charger 54 fed to a batteryenergy management system 56. The battery energy management system 56monitors and controls electricity to the batteries 44 and protects thebatteries 44. The battery energy management system 56 will turn offelectricity to the batteries 44 in the event that electricity is too lowor too high, either of which could result in damage to the batteries 44.The battery energy management system 56 basically load balances thebattery discharge and the charging of the batteries 44. Electricity fromthe battery energy management system 56 is provided to the batteries 44,here, preferably 12 V 100 aH lithium ion batteries 44. The batteries 44are connected to the external power switch 46 which turns on and off thesystem 10.

The batteries 44 are electrically connected to two seismic amplifiers 58which are in turn connected to a seismic transducer 36 to produce avibrating signal that is transmitted to the surface for communicationwith the surface. Also connected to the seismic amplifiers 58 is thefrequency generator 34 that receives input from the digital controloutputs 60 of the controller 12 and controls the vibration signal thatis ultimately transmitted by the seismic transducer 36. See U.S. Pat.No. 7,843,768, incorporated by reference herein, for details of theoperation of the transmission signal to the surface from the system 10.

The controller 12 also has a power sense 42 connected to the electricalpower switch 46 to determine when the system 10 is activated. Thecontroller 12 also has battery monitoring 40 connected to the batteries44 to monitor the charge of the batteries 44. The batteries 44 are alsoconnected to a 12 volt regulator 62 of the controller 12. The 12 voltregulator 62 is electrically connected to the frequency generator 34 andto a POD communicator 32 and to a downlink receiver 64 to power them.The POD communicator 32 in turn is connected to a DC block 66, which inturn is connected to the Commtrac antenna 68 in a first explosion proofenclosure 70 to power the Commtrac antenna 68. In addition, a first RSS232 level shifter 72 is in communication with the POD communicator 32through which messages are sent to and received from the Commtracantenna 68 in regard to communication with the miners. It should benoted that Commtrac is an example of a mesh network generally that canbe used with the present invention.

A second RS-232 level shifter 74 of the controller 12 is incommunication with the Ultra Receive Antenna 30 in a second explosionproof enclosure 76 through which messages are received from the surface.The downlink portion where signals are transmitted from the surface tothe Ultra Receive antenna 30 and the Ultra Receive board 64 waspurchased from Ultra Electronics Maritime Systems, Inc. in Nova Scotia,Canada.

Each explosion proof container is attached to the controller 12 throughan MSHA approved cable. This cabling is required by MSHA for intrinsicsafety reasons and is well known in the art.

As mentioned above, CommTrac is a well-known standalone communicationsand tracking system that operates by having nodes that are positionedideally on the ceiling of a mine. These nodes form a self-healingwireless network that is used as a backbone for transmitting data to thesurface. Data is received by each node and is transmitted to the next“hop” or node until it reaches the surface. The nodes are organized in atree structure so each node knows exactly what node it must send data toin order for it to reach the surface. Each node positioned on theceiling will send a status update once every 5 minutes to report batterylife and the state of the network as that node sees it. The miners carrypersonal devices, otherwise called here personnel communicators 28 thattransmit their location once per second by receiving the signal strengthof all the nodes around them. This data is sent to the surface wheretheir position is determined by having the server run an algorithm. Theserver can determine the location because it knows the geographicallocation of every node in the network. The miner's personal communicator28 can also send text messages through this network as well as receivethem.

When the system 10 is activated by the switch 46, then the node havingthe controller 12 turns into the Gateway of the CommTrac network or theroot of the tree. This root is normally on the surface, but since thatcommunication is assumed to be cut-off, the node with the controller 12will become this Gateway. All data will flow to the controller 12 of thesystem 10, but it will essentially only care about responses to thequestions asked from the surface. When a message is sent from thesurface, it is sent through the downlink portion 16 of the system 10 tothe controller 12, and then out the CommTrac network and downstreamthrough the network until it reaches all of the miners. This is wheneach miner will respond with the 1, 2, or 3 colors. These messages arereceived by the Gateway and passed to the controller 12 just as theywould in a surface server. But now the controller 12 filters for theresponses and accumulates them. Once all of the responses are received,a frequency/tone that corresponds to a number of responses is sent tothe surface by the controller 12.

Before the switch 46 is thrown, the CommTrac node that would become theGateway is only used to relay data to the surface Gateway and operateslike any other node of the CommTrac network. It will not pass any datait receives to the controller 12 in the system 10. After the switch 46is thrown, this node becomes the Gateway (endpoint for the data) so theCommTrac network will reconfigure itself to relay all data to the newGateway. Once the CommTrac node that has now become the gateway in thesystem 10 receives any data, it will be passed to the controller 12 inthe system 10. When the switch 46 is thrown, the controller 12 willre-program the CommTrac node parameters to tell it to become a gatewayfor the CommTrac network.

The switch 46 may be a lever physically located on the explosion proofenclosure 20, also called the Through the Earth (TTE) box. Until thatswitch 46 is thrown, the CommTrac node used in the system 10 just actslike any other node in the CommTrac network. Once the switch 46 isactivated, then this node converts itself to a CommTrac gateway thatcauses the other underground nodes to reconfigure to send data to it. Bythe switch 46 being thrown indicates the CommTrac underground networkhas lost communication with the surface or doesn't exist. Miners wouldtypically only want to use the system 10 if they had too becauseCommTrac communication had been destroyed.

In reconfiguration, the following occurs. The nodes are always searchingfor a parent to connect to and send data. This parent is decided byselecting the least number of hops to the root of the tree (theGateway). Once the node with the controller 12 becomes the root/Gateway,all of the nodes will automatically reconfigure to send data to itbecause it will now be broadcasting in its beacon that it has the leastnumber of hops.

Although the invention has been described in detail in the foregoingembodiments for the purpose of illustration, it is to be understood thatsuch detail is solely for that purpose and that variations can be madetherein by those skilled in the art without departing from the spiritand scope of the invention except as it may be described by thefollowing claims.

1. A communication system for allowing personnel in a tunnel belowground to communicate with a location above ground comprising: acontroller disposed below ground in the tunnel; an uplink portion thatsends uplink messages from the controller below ground in the tunnelthrough earth to above ground, the controller in communication with theuplink portion; a downlink portion through which downlink messages aresent from above ground through earth to the controller below ground inthe tunnel, the controller in communication with the downlink portion;and a personnel communication portion through which downlink messagesare sent from the controller wirelessly to the personnel as personnelmessages, and personnel messages, are received wirelessly by thecontroller from the personnel below ground in the tunnel, the controllerin communication with the personnel communication portion, the personnelcommunication portion having a plurality of nodes in the tunnel and asurface gateway above ground in communication with each other, thepersonnel communication portion in communication with above groundseparately from the uplink portion and the downlink portion, one node ofthe plurality of nodes having a switch which converts the one node to anew gateway node for the plurality of nodes when the personnelcommunication portion loses communication with above ground and thesurface gateway and causes other nodes of the plurality of nodes toreconfigure and send data to the new gateway node, the one node havingthe controller, after the switch is activated, the one node becomes thenew gateway node, as the new gateway node it becomes an endpoint for thedata, once the one node has become the new gateway node, any data thenew gateway node receives is passed to the controller and the controllertransmits the data to above ground through the uplink portion in theuplink messages, and once the one node has become the new gateway node,the new gateway node receives downlink messages from above groundthrough the downlink portion, the controller includes a processing unitwhich, once the one node has become the new gateway node, takes downlinkmessages received from the downlink portion and transmits the downlinkmessages as personnel messages to the personnel, and which takespersonnel messages received from the personnel communication portion andtransmits the personnel messages as uplink messages above ground throughthe uplink portion.
 2. The system as described in claim 1 wherein thecontroller is disposed in an intrinsically safe enclosure.
 3. The systemas described in claim 2 wherein the enclosure is explosion proof.
 4. Thesystem as described in claim 3 wherein the controller includes aprocessing unit which takes downlink messages received from the downlinkportion and transmits the downlink messages as personnel messages to thepersonnel, and which takes personnel messages received from thepersonnel communication portion and transmits the personnel messages asuplink messages above ground through the uplink portion.
 5. The systemas described in claim 4 wherein the controller includes an uplinkinterface through which uplink messages are provided to the uplinkportion, a downlink interface through which downlink messages arereceived from the downlink portion, and a personnel communicationinterface through which personnel messages are sent to and received fromthe personnel communication portion.
 6. The system of claim 5 whereinthe processing unit broadcasts out the downlink messages as personnelmessages to all personnel through the personnel communication portion.7. The system of claim 6 wherein the personnel communication portionincludes a personnel communicator disposed with each personnel thatsends a response to each personnel message received from the controllerback to the controller through the personnel communication portion. 8.The system of claim 7 wherein the response is either positive ornegative and the processing unit counts the responses that are positivewhich were received over a predetermined time period and sends an uplinkmessage at a frequency which corresponds to a number of responsescounted in the predetermined time that are positive which were receivedby the controller.
 9. The system of claim 8 wherein positive responsesare green responses and negative responses are red responses.
 10. Thesystem of claim 9 wherein the downlink portion uses magnetic inductionto send the above ground message to the tunnel.
 11. The system of claim10 wherein the uplink portion uses seismic waves to send the belowground message to above ground.
 12. The system of claim 11 including abattery and the controller includes a relay bank which preventselectrical feedback from the battery to external tunnel power.
 13. Acontroller for allowing miners in a tunnel below ground to communicatewith a location above ground comprising: an uplink interface with anuplink portion through which uplink messages are sent to the locationabove ground; a downlink interface with a downlink portion through whichdownlink messages are received from above ground; a personnelcommunication interface with a personnel communication portion throughwhich personnel messages are sent to and received from the personnelbelow ground in the tunnel; a switch which converts the controller to anew gateway node for a plurality of nodes when the personnelcommunication portion loses communication with above ground and thesurface gateway and causes other nodes of the plurality of nodes toreconfigure and send data to the new gateway node, after the switch isactivated, the controller becomes the new gateway node, as the newgateway node it becomes an endpoint for the data, once the controllerhas become the new gateway node, any data the new gateway node receivestransmits the data to above ground through the uplink portion in theuplink messages, and once the controller has become the new gatewaynode, the new gateway receives downlink messages from above groundthrough the downlink portion; and a processing unit which, once thecontroller has become the new gateway node, takes downlink messagesreceived from the downlink portion and transmits the downlink messagesas personnel messages to the personnel, and which takes personnelmessages received from the personnel communication portion and transmitsthe personnel messages as uplink messages above ground through theuplink portion.
 14. A method for allowing personnel in a tunnel belowground to communicate with a location above ground comprising the stepsof: a personnel communication portion having a plurality of nodes in thetunnel and a surface gateway above ground in communication with eachother, the personnel communication portion in communication with aboveground separately from an uplink portion and a downlink portion, onenode of the plurality of nodes having a switch, the switch convertingthe one node to a new gateway node for the plurality of nodes when thepersonnel communication portion loses communication with above groundand the surface gateway and causes other nodes of the plurality of nodesto reconfigure and send data to the new gateway node, the one nodehaving a controller, after the switch is activated, the one node becomesthe new gateway node, as the new gateway node it becomes an endpoint forthe data, once the one node has become the new gateway node, any datathe new gateway node receives is passed to the controller and thecontroller transmits the data to above ground through the uplink portionin the uplink messages, and once the one node has become the new gatewaynode, the new gateway node receives downlink messages from above groundthrough the downlink portion, the controller includes a processing unitwhich, once the one node has become the new gateway, takes downlinkmessages received from the downlink portion and transmits the downlinkmessages as personnel messages to the personnel, and which takespersonnel messages received from the personnel communication portion andtransmits the personnel messages as uplink messages above ground throughthe uplink portion; sending uplink messages as a frequency or tone fromthe controller through the uplink portion below ground in the tunnelthrough earth to above ground, the controller in communication with theuplink portion; sending messages from above ground through earth to thecontroller through the downlink portion below ground in the mine, thecontroller in communication with the downlink portion; sending from thecontroller through the personnel communication portion wirelessly to thepersonnel downlink messages as personnel messages, the controller incommunication with the personnel communication portion; and receivingwirelessly by the controller from the miners below ground in the tunnelpersonnel messages.
 15. The method as described in claim 14 includingthe steps of a processing unit of the controller taking downlinkmessages received from the downlink portion and transmitting thedownlink messages as miner messages to the personnel, and takingpersonnel messages received from the personnel communication portion andtransmitting the personnel messages as uplink messages above groundthrough the uplink portion.
 16. The method as described in claim 15including the steps of the controller providing uplink messages to theuplink portion through an uplink interface of the controller, providingdownlink messages received from the downlink portion to the processingunit through a downlink interface of the controller, sending personnelmessages to the personnel from the processing unit through a personnelcommunication interface of the controller; and receiving personnelmessages from the miners by the processing unit through the personnelcommunication portion.
 17. The method of claim 16 including the step ofthe processing unit broadcasting out the downlink messages as minermessages to all personnel through the personnel communication portion.18. The method of claim 17 wherein the personnel communication portionincludes a personnel communicator disposed with each personnel andincluding the step of sending from the personnel communicators aresponse to each personnel message received from the controller back tothe controller through the personnel communication portion.
 19. Themethod of claim 18 wherein the response is either positive or negative,and including the steps of the processing unit counting the responsesthat are positive which were received over a predetermined time periodand sending an uplink message at a frequency which corresponds to anumber of responses counted in the predetermined time that are positivewhich were receives by the controller.
 20. The method of claim 19wherein positive responses are green responses and negative responsesare red responses.
 21. The method of claim 20 including the step ofpreventing electrical feedback from a battery to external tunnel powerwith a relay bank of the controller.